Laparoscopic surgery is generally performed through small incisions in the abdomen using specialized instruments to accomplish the desired surgical procedures. Usually, the instruments are introduced through a narrow diameter tube, such as a trocar sleeve, while the physician observes manipulation of the instruments through specialized imaging equipment, such as a laparoscope. Laparoscopic surgical techniques offer significant advantages over conventional “open” surgical procedures, including better cosmetics effect, less postoperative pain, decrease resumption of gastrointestinal function and early return to work.
In laparoscopic surgical procedures, it is generally necessary to lift the abdominal wall away from the underlying abdominal organs to improve the visibility and accessibility of such organs. Such distension of the abdominal cavity, or peritoneum, has been heretofore accomplished by injecting a gas such as CO2 into the peritoneal cavity to tent-up the interior of the abdominal wall. The insufflation thus requires gas seals to be present at all entry ports through the abdominal wall; and, because of the doming effect on the abdomen, the laparoscopic instruments (graspers, scissors, electrocautery instruments, etc.) need long shafts to reach the treatment site. Further, using the insufflation technique, maintenance of the required distension is complicated by the loss of gas through the entry ports through the abdominal wall.
It has been proposed to use mechanical systems for peritoneal distension to overcome the problems associated with the insufflation technique. For example, U.S. Pat. No. 538,012 and Hashimoto et al. (Laparoscopic cholecystectomy: an approach without pneumoperitoneum, Surgical Endoscopy, 1994, pp. 54-56) adopts an alternative to abdominal insufflation, by upward and outward traction on the anterior abdominal wall with a hanger lifting method using subcutaneous wiring. However, the wires hung above the abdominal wall may obstruct the operators' actions during operation.
Chin et al. disclose the Laparofan® technique for lifting the abdominal wall by means of angle-shaped rods having elongated arms at their distal ends which are inserted through an incision and farmed out within the abdomen. (Gasless laparoscopy using a planar lifting technique, Journal of American College of Surgery, 1993, Vol. 178, pp 401-403) Most of Chin et al.'s patents mainly focus on the fan retractors. For example, U.S. Pat. No. 5,501,653 utilizes a pair of lifting rods each hinged at their distal ends to opposite ends of an elongate cross-member. After insertion, the apparatus is locked into the triangular configuration, connected to a lifting arm, and lifted to cause the retraction rods to lift and support the abdominal wall.
U.S. Pat. No. 5,505,689 discloses a fan retractor for laparoscopic surgery which has a pair of angle-shaped elements with first legs disposed in parallel relationship to one another and second legs extending laterally from the first legs for movement between a juxtaposed collapsed condition and a fanned-out expanded condition.
U.S. Pat. Nos. 5,569,165 and 5,690,607 provide an apparatus for allowing two fan retractors to be used to lift the abdominal wall and to provide improved visualization and working space in the abdomen of obese patients, and in the lateral regions of the abdomen of normal patients.
Similarly, U.S. Pat. No. 5,716,327 utilizes a lifting body having two or more retraction rods supported by the lifting body. The retraction rods are spread apart from each other while their parallel orientation is maintained. The lifting body is connected to a lifting arm and lifted, causing the retraction rods to lift and support the abdominal wall.
U.S. Pat. No. 5,823,946 discloses a mechanical lifting retractor to increase working space in the chest for cardiac surgery by temporarily expanding the space between the rib cage and the pericardium. The lifting device has a pair of parallel right-angled retractors. Following insertion of the distal portions into the mediastinal space, the distal portions are rotated into the lifting position and oriented in the sagittal plane such that each distal portion extends beneath one of the ribs. A lifting force is applied to the lifting retractor, causing the distal portions to engage the ribs and to lift the rib cage and thereby enlarging the mediastinal space.
All of these retractors or apparatus mentioned above require a mechanical lifting arm to provide the lifting force. However, none of these patents mentioned above fully disclosed the arm.
Chin et al.'s U.S. Pat. Nos. 5,372,147 and 5,555,897 do describe a mechanical lifting arm. The arm comprises a support structure including an extendible vertical post, an extendible horizontal arm, and means at the lower end of the post for mounting the structure to a surgical table. A mechanism is provided for releasably locking the position of the horizontal arm relative to the vertical post including an actuator switch at the distal end of the horizontal arm. Furthermore, the arm is provided for power-assisted raising and lowering of the vertical post. Although power assisted raising of the arm provides quick and controlled lifting of the body structure, the power requirement also made the system to be kind of complicated.
Furthermore, U.S. Pat. No. 5,704,900 also discloses an apparatus for peritonal distension with manual operation. The apparatus is a surgical instrument support structure including a substantially vertical post having a gear rack disposed generally along the post's axis and an arm assembly movably coupled along the gear rack extending from the gear rack for holding a surgical instrument. The arm assembly includes a circular gear rotatably coupled to the arm assembly in engagement with the gear rack and a mechanism for rotating the circular gear, whereby rotation of the circular gear raises and lowers the arm assembly relative to the vertical post. The '900 apparatus using the circular gear to raise and lower the whole arm including the distension instrument may also increase the possibility of structure instability. The apparatus is not only complicate but also has a support, elbow and distal end to increase the instability problem.
For these reasons, it would be desirable to provide improved apparatus for lifting the distension instrument, particularly for providing a stable lifting force during gasless laparoscopic surgical procedures. In particular, the apparatus should provide for lifting of the abdominal wall or other body structure without using power-assisted lifting and lowering. The apparatus should allow easily manual manipulation and stable support the lifting.